ambient noise reduction on input signal?

i’m using a variety of microphones for input via adc~ and would like some ambient noise reduction. the mac includes this feature on its built-in mic but not for other mics plugged into it (even USB ones). is there an easy way to get this feature in Max?

There was a recent thread here on a similar topic, and the consensus among those who replied was that removing ‘printed’ ambience is very tricky, and should be maximally reduced at the source using reflection filters etc.